PHPY 302 Lecture 2: CV System Notes 09.29.16
17 Oct 2016
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Origins of pressure in circulation (pg 418-419) Measurement of bp, bf, co (pg 420-428) Blood pressure is pressure difference between two points. Bp is often gauged by the height it can drive a column of liquid. P = pressure (pascals, g/cm2, or dynes/cm2) = density of liquid (mercury or h2o) This is not reflective of the absolute bp but rather the difference in pressure between the inside of the vessel and the barometric pressure (atmosphere). The pressure difference between 2 points is always separated by some distance (spatial orientation relative to one another). There are 3 kinds of pressure differences in circulation. Driving pressure: pressure difference between x1 and x2. Transmural pressure: pressure difference between the inside of the vessel r1 (intravascular pressure) and just outside the vessel r2 (tissue pressure). This governs vessel diameter, the major determinant of resistance. Hydrostatic pressure: pressure difference between h1 and h2. Due to density of blood and gravitational forces.
